Siren whistle



Sept. 9', 1924. 1,508,330'- F. B. HOWELL S IREN WHISTLE Filed Dec. 27. 1921 Fig.2.

Inventor: Fr ed B.Howeil His Attorney.

Patented Sept. 9, 1924.

UNITED STATES 'PATENTOFFICE.

FRED 1B. HOWELL, F SCI-IENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A. CORPORATION OF NEW YORK. 4

SIREN WHISTLE.

Application filed December 27, 1921. Serial No. 524,978.

To all whom it may concern:

Be it known that I, FRED B. HOWELL, a citizen of the United States, residing at at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Siren Whistles, of which the following is a specification.

My invention relates to sound producing devices, such as sirens and the like which depend upon the periodic emission of impulse jet-s or blasts of elastic fluid, such as air under pressure, for setting up the sound disturbances.

In carrying out my invention in one form I utilize a flexible pressure tube for automatically controlling the production of the periodic blasts of elastic fluid. Flexible pressure tubes of this general character are commonly known under the name of Bourdon tubes. Such a tube can be made to move very rapidly in response to changes in pressure within the tube. I utilize this characteristic of the tube to produce rapid blasts or impulses of air or gas, such impulses being produced in a confined space as, for instance, in the usual funnel or megaphone.

In the accompanying drawing illustrating one embodiment of my invention, Fig. 1 is a view partly in section illustrating the general features of my invention; Fig. 2 is a slight modification; Fig. 3 is a sectional view of the same; and Figs. 4 and 5 show details.

Referring first to Fig. 1, represents a flexible tube to which the pressure of elastic fluid, such as air or other gas under compression, is admitted to the openings 11. This part 11 is, of course, fixed by being attached to some source of fluid pressure. The free end of this tube 12 cooperates with a horn or megaphone 13, through an opening 14: in the end of the funnel. A similar opening 15 in the end of the tube 10 permits the passage of air from the tube into the funnel whenever the openings 14 and 15 are in register. The openings 14 and 15 are of proper width and in Fig. 5 I have shown tube 10 expanded to a considerable width making the opening 15 a narrow elongated slot. The opening 14 will, of course, be made to correspond.

It will be understood that the tube 10, which is shown bent, tends to straighten out when pressure is applied, and to contract when the pressure is relieved. When the pressure reaches a proper point, therefore,in the tube 10, the end 12 of the tube will move upward in Fig. 1, until the openings 14% and 15 are in register. Then this happens the pressure of air in the tube 10 will be relieved into the funnel 13. As soon asthis happens the tube will again contract and close the opening between the tube and the funnel. By proper adjustment of the parts, this opening and closing of the tube and the consequent blasts of air drawn into the funnel 13 will be very rapid, the rapidity depending upon the proportion of the parts. These blasts of air in the funnel 13 set up waves which produce a note depending upon the number of vibrations per second.

In Fig. 2 I have shown the end of the tube 10 supported in a yoke 16, the openings 17 and 18 being provided as before. There is also provided an opening 19 for balancing part of the end of the tube within the yoke so as to prevent binding. The tube 10 in this case is bent into a somewhat different form from 1, but otherwise the arrangeient and mode of operation are the same as that described with reference to Fig. 1.

While I have described my invention as embodied in concrete form and as operating in a. specific manner in accordance with the provisions of the patent statutes, it should be understood that I do not limit my invention thereto, since various modifications thereof will suggest themselves to those skilled in the art without departing from the spirit of my invention, the scope of which is set forth in the annexed claims.

What I claim as new and desire to secure by Letters Patent of the United States, is,

1. A sound producing device comprising a flexible pressure tube having one end free to move in accordance with changes in pressure within the tube, said end being provided with an exhaust opening, and means cooperating with said tube for controlling said opening in response to movement of said end so that the pressure in said tube is alternately released and confined by the movement of said end due to said changes in pressure in the tube whereby a succession of sound producing waves is emitted from said opening.

2. A sound producing device comprising a megaphone provided with an inlet opening, a flexible pressure tube having an openopening normally closed thereby but adapt-- ed to register With said inlet opening upon the occurrence of a predetermined pressure, and means for applying a fluid pressure to said device whereby said device is caused to alternately expand and contract and exhaust said fluid in a succession of sound producing blasts into said amplifier.

In Witness wherof, I have hereunto set my hand this 22nd day of December, 1921.

FRED B. HOWELL. 

